<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in levelList" :key="item.path">
        <span
          class="no-redirect"
          v-if="item.redirect === 'noRedirect' || index == levelList.length - 1"
          v-text="item.meta.title"
        ></span>
        <a
          v-else
          @click.prevent="handleLink(item)"
          v-text="item.meta.title"
        ></a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script>
import pathToRegexp from 'path-to-regexp'

export default {
  name: 'Breadcrumb',
  data() {
    return {
      levelList: null,
    }
  },

  watch: {
    $route(route) {
      // if you go to the redirect page, do not update the breadcrumbs
      if (route.path.startsWith('/redirect/')) {
        return
      }
      this.getBreadcrumb()
    },
  },

  methods: {
    getBreadcrumb() {
      // 获取 当前路由的 父子集合 this.$route.matched
      // 筛选出 matched 的子集大于1 说明是父子集
      // console.log(this.$route.matched)
      let matched = this.$route.matched.filter(
        (item) => item.meta && item.meta.title
      )

      if (!this.isDashboard(matched[0])) {
        // 添加父级
        matched = [{ path: '/dashboard', meta: { title: 'Dashboard' } }].concat(
          matched
        )
      }

      this.levelList = matched.filter(
        (item) => item.meta && item.meta.title && item.meta.breadcrumb !== false
      )
    },

    isDashboard(route) {
      const name = route && route.name
      if (!name) {
        return false
      }
      // 小写字母
      return name.trim().toLocaleLowerCase() === 'Dashboard'.toLocaleLowerCase()
    },

    handleLink(item) {
      const { redirect, path } = item
      console.log(item)
      // return
      if (redirect) {
        this.$router.push(redirect)
        return
      }
      this.$router.push(this.pathCompile(path))
    },
    pathCompile(path) {
      // To solve this problem https://github.com/PanJiaChen/vue-element-admin/issues/561
      const { params } = this.$route
      var toPath = pathToRegexp.compile(path)
      return toPath(params)
    },
  },
}
</script>

<style lang="scss" scoped>
.app-breadcrumb.el-breadcrumb {
  display: inline-block;
  font-size: 14px;
  line-height: 50px;
  margin-left: 8px;

  .no-redirect {
    color: #97a8be;
    cursor: text;
  }
}
</style>
